MSc Dissertation: Doreen Agaba

Citation:

Agaba, Doreen. Calibration of a SuperDARN Radar Antenna by means of a Satellite Beacon. MPhil Dissertation. Department of Electrical Engineering, University of Cape Town, 2012.

Abstract:

This dissertation reports on the investigation to determine which orbits, ionospheric conditions and seasons of the year that will facilitate the reception of the high frequency (HF) beacon signal from the 1 U CubeSat ZACUBE 1 by the SuperDARN HF radar in Antarctica, and by the HF direction-finding (DF) systems in both Pretoria and Hermanus.

The primary objective of the HF beacon on ZACUBE 1 is to provide a continuous radio signal to calibrate and verify the elevation-resolving algorithm of the SuperDARN HF Radar antenna at SANAE IV in Antarctica. The signal will also be used to characterise the beam pattern of this and other HF radar antennas in the SuperDARN network, and to characterise the ionosphere over the Earth’s polar region.

A secondary objective of the HF beacon on the satellite is to measure the ionospheric total electron content (TEC) by using either measurements of the carrier phase delays or of the Faraday rotation of the signal. An orbit analysis was done for the CubeSat using parameters for an orbit at an altitude of 600 km and inclination angles of 97.8° and 65°. To account for the propagation effects of the radio wave at 14.099 MHz, the IRI-2007 model and the Chapman layer model were used to define the ionosphere. A ray tracing algorithm written in MATLAB was used to simulate the ray paths. To evaluate the results, a documented ray tracing algorithm known as Haselgrove ray tracing was used.

The results obtained show that for an orbit at an inclination above 70° and altitude of 600 km, a number of rays actually traverse the ionosphere and reach the receivers during most of the year for a sufficient period of time during every pass. The least refraction is experienced during winter, therefore it is the best time for the calibration of the radar antenna. The results indicate that the objectives of the CubeSat mission should be achieved.